Daily Mirror article ref Flybe 146 and ice
Thread Starter
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From: on the fence
Daily Mirror article ref Flybe 146 and ice
Article in todays Daily Mirror (17/01) alledges that a Flybe 146 en-route LGW-BHD lost 3 engines due to ice problems and quote " hero pilot managed to start then again at 5000`" . Now leaving aside the usual jornu bull!!!!! , is there any truth in this ?
The Cooler King
Joined: Feb 2004
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From: Europe
All sounds a bit suspect.
But you know some journalists.......losing the same engine three times and restarting it could probably be twisted around to losing three engines - grammar is such a difficult art to master for some of them, although they seem to have gotten b@llsh!t down to a fine one!
But you know some journalists.......losing the same engine three times and restarting it could probably be twisted around to losing three engines - grammar is such a difficult art to master for some of them, although they seem to have gotten b@llsh!t down to a fine one!
Joined: Jan 1999
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From: Dublin
Does indeed sound like textbook ' Rollback'.
Well known problem familiar to all 146 operator's which I thought had been 'modded' out at this stage. When we were operating them we had a FL260 limitation to avoid the issue, but there have been several reported incidents of the same happening. The tech guru's can correct me but I beleive the icing occurs somehwhere behind the first stage fan and can affect all 4 donkey's at the same time
Well known problem familiar to all 146 operator's which I thought had been 'modded' out at this stage. When we were operating them we had a FL260 limitation to avoid the issue, but there have been several reported incidents of the same happening. The tech guru's can correct me but I beleive the icing occurs somehwhere behind the first stage fan and can affect all 4 donkey's at the same time
Per Ardua ad Astraeus
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From: UK
"The phenomenon of uncommanded thrust reduction (rollback) is known to occur at altitudes above 26,000 feet in temperature conditions of ISA +9 degrees C. or greater and in the vicinity of thunderstorm activity. . .Except for descent, flight in icing conditions above 26,000 feet and at an outside air temperature above -40 degrees C. SAT is prohibited within thirty nautical miles of thunderstorms.
X-XXXX was equipped with four Honeywell (formerly Allied Signal) ALF502R engines, each rated at 6,970 pounds of thrust. According to Honeywell, when operating at or above FL280 and in certain temperature and moisture conditions, the engines become susceptible to accumulating ice on the supercharger exit guide vanes (EGV). This reduces core engine airflow, resulting in a loss of power."
X-XXXX was equipped with four Honeywell (formerly Allied Signal) ALF502R engines, each rated at 6,970 pounds of thrust. According to Honeywell, when operating at or above FL280 and in certain temperature and moisture conditions, the engines become susceptible to accumulating ice on the supercharger exit guide vanes (EGV). This reduces core engine airflow, resulting in a loss of power."
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From: Kununurra
Originally Posted by CaptHairDryer
Ansett Australia (VH-JJP) had all 4 donks flame out many years back enroute to Perth, managed a restart at an alt I am not sure of!
http://www.atsb.gov.au/publications/...199200286.aspx
Joined: Oct 2001
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From: UK
This sort of thing used to happen to the CFM56 in heavy precipitation. I can recall Air Europe losing both engines on a 737-300 going into Thessaloniki. I also know of a DC-8-73 that lost three out of the four descending into Miami.
I presume they have all been modified.
I presume they have all been modified.
Per Ardua ad Astraeus
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From: UK
JW - a mod to 'flatten' the N1 spinner, plus I think some changes in the intake (?'splitter'?) on the 56. Still some placards around warning about 'unmodified' engines and min RPM in icing.
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From: Euroland
You would have to be really unlucky to find the right conditions for rollback in winter, and in any case all the engines should have been modded a couple of years ago.
Also, rollback is not necessarily an engine failure per se, it is a rising TGT and decaying RPM that MAY, if not recognised, lead to a pilot-induced shutdown of the engine. Well, I suppose the thing would fail eventually...
The importance of that is that you don't necessarily lose all your services (hydraulics and generators).
The point about the Aussie case was also that it was mis-handled by the crew.
Also, rollback is not necessarily an engine failure per se, it is a rising TGT and decaying RPM that MAY, if not recognised, lead to a pilot-induced shutdown of the engine. Well, I suppose the thing would fail eventually...
The importance of that is that you don't necessarily lose all your services (hydraulics and generators).
The point about the Aussie case was also that it was mis-handled by the crew.
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From: Euroland
Yeah I didn't mean that they mishandled it in the sense that they screwed up, but that they carried out some incorrect actions due to deficiencies in the information they had at the time.
These days I would imagine you would have to be very unlucky to have a bad rollback encounter, most if not all the engines are modded and the procedures for dealing with are well known to crews (including in the sim).
From the report (VH-JJP incident):
These days I would imagine you would have to be very unlucky to have a bad rollback encounter, most if not all the engines are modded and the procedures for dealing with are well known to crews (including in the sim).
From the report (VH-JJP incident):
The possibility of engine roll-back during high altitude cruise in high ambient temperatures, with engine and airframe anti-ice on, was addressed by the aircraft manufacturer in several Notices to Aircrew prior to the VH-JJP occurrence.
Significant factors
1. During high altitude cruise, the aircraft encountered a pool of moist air which was significantly warmer than the surrounding air.
2. The selection of engine and airframe anti-ice by the crew placed a bleed air demand at, or slightly above, the maximum on the four engines, causing them to ‘roll back’.
3. An Operational Notice published by the aircraft manufacturer did not provide information of sufficient clarity to enable the crew to recognise and deal with the ‘roll-back’.
4. Engine core icing probably prevented the recovery from the ‘roll-back’ until the aircraft descended below the freezing level.
1. During high altitude cruise, the aircraft encountered a pool of moist air which was significantly warmer than the surrounding air.
2. The selection of engine and airframe anti-ice by the crew placed a bleed air demand at, or slightly above, the maximum on the four engines, causing them to ‘roll back’.
3. An Operational Notice published by the aircraft manufacturer did not provide information of sufficient clarity to enable the crew to recognise and deal with the ‘roll-back’.
4. Engine core icing probably prevented the recovery from the ‘roll-back’ until the aircraft descended below the freezing level.
